Answer:
x≥(500-87)/40
Step-by-step explanation:
You require 500 lbs and you're starting with 87, so you must acquire at least 413 bags. Since they are sold in 40 pound bags, you divide by 40. You must round up to ensure you have enough bags to meet the 500 lbs needed.
An equation of the form

describes a line
that passes through the origin and whose tangent corresponds to

. Generally, any equation formatted as

represents a line.